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Objective: To describe trends in incidence, treatment and survival of patients with basal cell carcinomas and melanomas of the vulva. Also to compare survival of vulvar and cutaneous melanoma patients., Methods: All women with a vulvar malignancy between 1989 and 2012 were selected from the Dutch Cancer Registry (n=6436). Standardized incidence rates, estimated annual percentage change (EAPC) and 5-year relative survival rates were calculated for basal cell carcinomas (BCCs) and melanomas. Patients with vulvar melanomas were matched to women with cutaneous melanomas on period of diagnosis, age, Breslow thickness, tumour ulceration, lymph node status and distant metastases. Differences in survival were evaluated using Kaplan-Meier curves and the log rank test., Results: 489 women were diagnosed with a BCC and 350 with a melanoma of the vulva. The EAPC in incidence for melanomas was 0.2% and 1.1% for BCCs. Eighty-six percent of patients with BCC underwent surgical treatment in 1989-2006 and 95% in 2005-2012. Forty-five percent with BCC and 79% with melanoma were treated in a referral centre. Five-year relative survival for BCCs was 100% and for melanomas survival increased from 37% (95%CI 28-47%) in 1989-1999 to 45% (95%CI: 37-54%) in 2000-2012. Five years after diagnosis survival of women with vulvar melanoma was 15% lower compared to matched cutaneous melanoma patients (p=0.002)., Conclusion: No trends in age-adjusted incidence have been observed but more patients with BCC received surgical treatment over time. Having had vulvar BCC did not affect life expectancy. Well-known prognostic factors explained most of the differences in survival between cutaneous and vulvar melanoma patients, however a difference of 15% remained unexplained., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objective: The overall 5-year survival of patients with vulvar squamous cell carcinoma (SCC) is 70%. The clinical impression is that localization of SCC on the clitoris may lead to worse prognosis. The aim of this study is to assess the disease specific survival (DSS) in patients with clitoral SCC compared to patients with SCC without clitoral involvement., Methods: All consecutive patients with primary vulvar SCC treated with surgery at the Department of Gynaecologic Oncology at the Radboud university medical centre (Radboudumc) between March 1988 and January 2012, were analysed. The clinical and histopathological characteristics and DSS rates of patients with (N = 72) and without clitoral SCC (N = 275) were compared. Furthermore, patients with clitoral involvement were compared to patients with perineal SCCs (N = 52) and other central SCCs without clitoral and/or perineal involvement (N = 117)., Results: Patients with clitoral SCC more often had larger and deeper invaded tumours, lymphovascular space involvement (LVSI), positive surgical margins and a higher percentage of positive lymph nodes. Kaplan-Meier survival analyses showed worse DSS in patients with a clitoral SCC compared to patients without clitoral involvement. Multivariable analysis showed that not clitoral involvement, but invasion depth, differentiation grade and lymph node status are independent prognostic factors., Conclusions: Patients with clitoral SCC have worse survival compared to patients without clitoral involvement. This is probably caused by unfavourable histopathological characteristics of the tumour rather than the localization itself. Prospective studies are needed to further assess the influence of localization of the vulvar SCC on prognosis., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Depth of invasion is an important prognostic factor for patients with vulvar squamous cell carcinoma. The aim of this study was to identify the most optimal method of measuring the depth of invasion in relation to the individual outcome in patients with vulvar squamous cell carcinoma. Data of 175 consecutive patients with a primary vulvar squamous cell carcinoma with known lymph node status, treated in the Radboud University Medical Center, the Netherlands (2000-2010), were stored in a database. At pathology review of 148 (85%) cases, depth of invasion was measured using the conventional and alternative methods. Clinical and pathological characteristics of patients with a change in FIGO stage were compared with those without a change in stage. In 148 vulvar squamous cell carcinoma patients, the median depth of invasion was shown to be decreased from 5.5 mm (range 1.1-20) using the conventional method to 3.6 mm (range 0.2-20) using the alternative method (P<0.05). This led to a change in the FIGO stage in 13 of the 148 (9%) patients and a change in depth of invasion from 3.5 to 0.2 mm in one patient (1%) with FIGO stage IIIA. Of all 69 stage 1B patients, 13 (19%) were downstaged to stage IA. The downstaged patients developed less recurrences (15% vs 39%) and had a higher disease-specific survival (100% vs 84%) compared with the patients who remained FIGO stage IB. Using the alternative method for measuring the depth of invasion in tumors of vulvar squamous cell carcinoma patients, 19% of the patients with a FIGO stage IB tumor might be treated without groin surgery resulting in less treatment-related morbidity. The results are promising but more prospective data on a higher number of patients are necessary.

Aim: Previous studies showed an increase in incidence of vulvar intraepithelial neoplasia (VIN), the premalignant lesion of Vulvar Squamous Cell Carcinoma (VSCC). Furthermore, during the last decades treatment of VSCC became less radical. Considering these changes the aim of this study was to describe trends of incidence and survival of patients with VSCC in the Netherlands., Methods: All patients with VSCC diagnosed between 1989 and 2010 (n=4614) were selected from the Netherlands Cancer Registry. Trends in age-adjusted incidence rates were evaluated by calculating the estimated annual percentage change (EAPC). Joinpoint regression analysis was used to detect changes in trends. Five-year relative survival rates were calculated for four time periods., Results: The incidence of VSCC has increased since 2002 (EAPC 5.0; 95% confidence interval (CI): 2.7-7.7%). In women aged <60years incidence rates increased significantly during the whole study period (EAPC 3.5%; 95% CI: 2.0-4.9), while in women aged ≥ 60 years only an increase has observed from 2004 onwards (EAPC 5.0; 95% CI: 1.5-8.6). Survival rates did not change over time., Conclusion: The incidence rate of VSCC has increased from 2002 onwards in all women. Over the whole study period the increase was strongest in women aged <60 years. The introduction of less radical surgery did not affect survival., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

No published data concerning intraobserver and interobserver variability in the histopathological diagnosis of differentiated vulvar intraepithelial neoplasia (DVIN) are available, although it is widely accepted to be a subtle and difficult histopathological diagnosis. In this study, the reproducibility of the histopathological diagnosis of DVIN is evaluated. Furthermore, we investigated the possible improvement of the reproducibility after providing guidelines with histological characteristics and tried to identify histological characteristics that are most important in the recognition of DVIN. A total number of 34 hematoxylin and eosin-stained slides were included in this study and were analyzed by six pathologists each with a different level of education. Slides were reviewed before and after studying a guideline with histological characteristics of DVIN. Kappa statistics were used to compare the interobserver variability. Pathologists with a substantial agreement were asked to rank items by usefulness in the recognition of DVIN. The interobserver agreement during the first session varied between 0.08 and 0.54, which slightly increased during the second session toward an agreement between -0.01 and 0.75. Pathologists specialized in gynecopathology reached a substantial agreement (kappa 0.75). The top five of criteria indicated to be the most useful in the diagnosis of DVIN included: atypical mitosis in the basal layer, basal cellular atypia, dyskeratosis, prominent nucleoli and elongation and anastomosis of rete ridges. In conclusion, the histopathological diagnosis of DVIN is difficult, which is expressed by low interobserver agreement. Only in experienced pathologists with training in gynecopathology, kappa values reached a substantial agreement after providing strict guidelines. Therefore, it should be considered that specimens with an unclear diagnosis and/or clinical suspicion for DVIN should be revised by a pathologist specialized in gynecopathology. When adhering to suggested criteria the diagnosis of DVIN can be made easier.

Introduction: In general, centralisation of care for patients with rare malignancies is advised in order to improve outcome with respect to prognosis and treatment related morbidity. Therefore, centralisation of women with vulvar squamous cell carcinoma (SCC), which is an extremely rare tumour, has been advocated by the national guidelines of the Dutch Society of Obstetrics and Gynaecology in 2000. The objective of this study was to determine whether this advice has been adapted and has led to improved survival., Methods: All patients diagnosed with vulvar malignancies between 1989 and 2008 in the Eastern part of the Netherlands were retrieved from the population-based cancer registry held by the Comprehensive Cancer Centre, The Netherlands. Patient- and tumour characteristics and vital status until January 2011 were retrieved. Data of patients diagnosed in two periods (before and after release of the guideline; 1989-1999 and 2000-2008) were compared. Relative survival rates were calculated as a good approximation of cause-specific survival., Results: A total number of 382 patients with vulvar SCC with invasion > 1mm, who had an indication for groin surgery, were included in the analysis. In the first decade 62% (123 of 198 patients) were treated in a specialised oncology centre, which increased to 93% (172 of 184 patients) in the more recent period. Overall, the 5 year relative survival improved slightly from 69% (95% confidence interval (CI) 60-77%) to 75% (95% CI 65-83%). After adjustment for age and stage, being treated in a specialised oncology centre was an independent prognostic factor for survival., Conclusion: Centralisation of care for vulvar SCC patients has been well adopted in the Eastern part of the Netherlands. Being treated in a specialised oncology centre was associated with a better survival after adjustment for age and stage., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Objective: Taking a biopsy is a standard procedure to make the correct diagnosis in patients with suspicious premalignant vulvar lesions. The use of a less invasive diagnostic tool as triage instrument to determine whether biopsy is necessary may improve patient comfort especially in patients with chronic vulvar disorders that may warrant consecutive biopsies. This study was conducted to investigate whether vulvar brush cytology is feasible and may be used to detect (pre)malignant vulvar lesions., Methods: A pilot study was performed with patients having clinically normal vulvar skin, lichen sclerosus (LS), usual or differentiated vulvar intraepithelial neoplasia or squamous cell carcinoma. A total of 65 smears were taken with the use of a vulvar brush and biopsies were performed for histopathological analysis., Results: Out of 65 smears, 17 (26%) were discarded because of poor cellularity. A total of 28 of 29 (97%) smears with a histological proven (pre)malignancy had a smear classified as 'suspicious' or 'uncertain'. Cytology classified 11 smears as 'non-suspicious', of which 10 (91%) were indeed normal skin or LS. The accuracy, based on the presence of a lesion, for (pre)malignant lesions with the use of the brush showed a sensitivity of 97% and a negative predictive value of 88%., Conclusion: Vulvar brush cytology is feasible and may be a first step in the development of a triage instrument to determine whether subsequent biopsy of a clinically (pre)malignant lesion is necessary.

Background: The cornerstone of treatment in early-stage squamous cell carcinoma (SCC) of the vulva is surgery, predominantly consisting of wide local excision with elective uni- or bi-lateral inguinofemoral lymphadenectomy. This strategy is associated with a good prognosis, but also with impressive treatment-related morbidity. The aim of this study was to determine risk factors for the short-term (wound breakdown, infection and lymphocele) and long-term (lymphoedema and cellulitis/erysipelas) complications after groin surgery as part of the treatment of vulvar SCC., Methods: Between January 1988 and June 2009, 164 consecutive patients underwent an inguinofemoral lymphadenectomy as part of their surgical treatment for vulvar SCC at the Department of Gynaecologic Oncology at the Radboud University Nijmegen Medical Centre. The clinical and histopathological data were retrospectively analysed., Results: Multivariate analysis showed that older age, diabetes, 'en bloc' surgery and higher drain production on the last day of drain in situ gave a higher risk of developing short-term complications. Younger age and lymphocele gave higher risk of developing long-term complications. Higher number of lymph nodes dissected seems to protect against developing any long-term complications., Conclusion: Our analysis shows that patient characteristics, extension of surgery and postoperative management influence short- and/or long-term complications after inguinofemoral lymphadenectomy in vulvar SCC patients. Further research of postoperative management is necessary to analyse possibilities to decrease the complication rate of inguinofemoral lymphadenectomy; although the sentinel lymph node procedure appears to be a promising technique, in 50% of the patients an inguinofemoral lymphadenectomy is still indicated.

Lichen sclerosus is considered to be the precursor lesion of vulvar squamous cell carcinoma, of which only 2-5% progress to squamous cell carcinoma. Differentiated vulvar intraepithelial neoplasia (VIN) has been proposed to be the direct precursor lesion, but this is a recently recognized, and a difficult to diagnose, entity, which may easily be mistaken for a benign dermatosis. The aim of this study was to test the hypothesis that of all lesions that have been diagnosed as lichen sclerosus in the past, a part might currently be diagnosed as differentiated VIN, and to identify histopathological differences between lichen sclerosus lesions with and without progression to vulvar squamous cell carcinoma. All lichen sclerosus slides were revised by two expert gynecopathologists and histopathological characteristics were documented. After revision of lichen sclerosus biopsies without progression (n = 61), 58 were reclassified as lichen sclerosus. Revision of lichen sclerosus biopsies with progression yielded concordant diagnoses in 18 of 60 cases (30%). Of 60 lesions, 25 (42%) were reclassified as differentiated VIN. The median time from differentiated VIN to vulvar squamous cell carcinoma was shorter (28 months) than that from lichen sclerosus to vulvar squamous cell carcinoma (84 months) (P < 0.001). Lichen sclerosus that progressed to squamous cell carcinoma, but did not meet the criteria for differentiated VIN, more often showed parakeratosis (P = 0.004), dyskeratosis (P < 0.001), hyperplasia (P = 0.048) and basal cellular atypia (P = 0.009) compared with lichen sclerosus without progression. In conclusion, differentiated VIN diagnosis has been frequently missed and is associated with rapid progression to squamous cell carcinoma. Patients with lichen sclerosus with dyskeratosis and parakeratosis, hyperplasia and/or basal cellular atypia should be kept under close surveillance as these lesions also tend to progress to squamous cell carcinoma.

Intratumoral hypoxia has been associated with poor prognosis in several solid tumors. The aim of this study was to determine whether the hypoxia-associated markers glucose transporter (GLUT)-1 and carbonic anhydrase (CA)-IX expression and preoperative hemoglobin (Hb) levels correlate with presence of inguinofemoral or distant metastases, and disease-free survival (DSS) in vulvar squamous cell carcinoma (SCC) patients. Vulvar SCC (n=103) were reviewed for histopathological characteristics by an expert gynecopathologist and stained for GLUT-1 and CA-IX. Clinical data and preoperative Hb levels were obtained from medical records. No significant correlations were observed between GLUT-1 or CA-IX expression patterns and preoperative Hb levels, presence of inguinofemoral or distant metastases and DSS. However, anemic patients (Hb<11.2 g/dL) had significantly more inguinofemoral metastases and lower Hb level was an independent prognostic factor for a worse DSS (p<0.001). The number of comorbidic conditions was inversely correlated with preoperative Hb level. Preoperative Hb levels are associated with poor DSS for vulvar SCC patients, whereas tumor hypoxia reflected by GLUT-1 and CA-IX expression does not have a predictive value. Because preoperative Hb levels inversely correlated with the number of comorbidic conditions and not with GLUT-1 or CA-IX expression, it is most likely that preoperative Hb levels represent overall physical condition.

The molecular pathogenesis of human papilloma virus-unrelated vulvar squamous cell carcinoma is not well known. Whether malignant progression of lichen sclerosus and differentiated vulvar intraepithelial neoplasia to vulvar squamous cell carcinoma could be accompanied by altered DNA content has not been studied extensively. DNA content in isolated nuclei of microdissected normal vulvar epithelium (n = 2), lichen sclerosus (n = 9), differentiated vulvar intraepithelial neoplasia (n = 13), and squamous cell carcinoma (n = 17) from 22 patients was measured via DNA image cytometry. For additional analysis, 6 differentiated vulvar intraepithelial neoplasia lesions were selected, bringing the number of patients to 28. p53 expression was determined by immunohistochemistry on consecutive tissue sections. Thirty-eight percent (5/13) of differentiated vulvar intraepithelial neoplasia lesions and 65% (11/17) of squamous cell carcinomas were DNA aneuploid or tetraploid. In lesions that contained differentiated vulvar intraepithelial neoplasia and adjacent squamous cell carcinoma, the ploidy status of differentiated vulvar intraepithelial neoplasia did not exceed that of squamous cell carcinoma. We observed a strong correlation between high p53 expression and DNA aneuploidy. This relation was also present at the level of a single nucleus, measured by sequential image cytometry of p53 immunohistochemistry followed by DNA image cytometry on formalin-fixed tissue sections. Similarly, we found p53-positive nonproliferating cells with increased DNA content in the superficial compartment of 6 additional solitary differentiated vulvar intraepithelial neoplasia lesions that were not associated with squamous cell carcinoma, indicating ascending aneuploid cells from the basal compartment. DNA ploidy measurements suggest that differentiated vulvar intraepithelial neoplasia has a higher malignant potential than lichen sclerosus and thus is a more likely precursor of squamous cell carcinoma. Furthermore, high p53 expression correlates with increased DNA content and aneuploidy; but it requires further research to unveil a possible causal relation., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Aims: The aetiology of vulvar squamous cell carcinomas (SCC) that are not causally associated with high-risk human papillomavirus remains largely elusive. The aim of this study was to analyse the inflammatory response in its presumed precursor lesions, lichen sclerosus (LS) and differentiated vulvar intraepithelial neoplasia (dVIN), and provide evidence that dVIN is a likely precursor of vulvar SCC., Methods and Results: Immunohistochemical analyses for CD4+, CD8+, CD20+, CD68+, S100+ and tryptase-positive immune cells were performed and quantified in LS (n = 7), dVIN (n = 19), SCC (n = 11), and normal vulvar tissue (n = 8). The subepithelial inflammatory response in dVIN and SCC was comparable, but absent in LS. Abundant intraepithelial mast cells were observed in dVIN only, and confirmed by electron microscopy, toluidine blue staining and cKIT expression. Adjacent keratinocytes displayed increased proliferation as determined by MIB-1 positivity. Electron microscopy revealed intraepithelial mast cell degranulation. Intraepithelial mast cells were not or infrequently observed in vulvar hyperplasia (n = 13), condylomata acuminata (n = 5), keratinocytic intraepidermal neoplasia of sun-exposed skin (n = 15), epidermal hyperplasia of head and neck (n = 12), and psoriasis (n = 3)., Conclusions: These data indicate that dVIN can be recognized by intraepithelial mast cells and that they might promote the progression of dVIN to SCC., (© 2010 Blackwell Publishing Limited.)

Objective: The objective of the study was to quantify vessel type and density in lichen sclerosus (LS) to find a marker for its malignant potential., Study Design: Quantitative analysis was performed on paraffin-embedded tissue samples of 28 patients with LS (7 adjacent to vulvar squamous cell carcinoma, 21 solitary) and immunohistochemical staining for CD34 (vascular and lymphangiogenic lymph endothelial cells), D2-40 (lymphatic-specific marker), and alpha-SMA (pericyte marker). Electron microscopy was performed on fresh tissue., Results: No significant differences in vessel density or other vessel parameters could be demonstrated between the 2 groups. In hyalinized lesions, vessel diameter, and alpha-SMA positivity was reduced compared with nonhyalinized lesions. Electron microscopy revealed detachment of pericytes from vascular endothelial cells and increased thickening of basement membrane, whereas endothelial cell function did not appear strongly impaired., Conclusion: Malignant potential of LS cannot be predicted by vessel characteristics. Hyalinization in LS is associated with pericyte detachment from the basal lamina of vascular endothelial cells., (Copyright (c) 2010 Mosby, Inc. All rights reserved.)

Background: Vulvar squamous cell carcinoma (SCC) originates the following two pathways, related to differentiated (d) vulvar intraepithelial neoplasia (VIN) or to human papillomavirus (HPV)-related usual (u) VIN. Multicentric HPV infections (cervix, vagina and vulva) are common. We hypothesise that patients with a uVIN-related vulvar SCC more often have cervical high-grade squamous intraepithelial lesions (HSILs) compared with women with dVIN-related vulvar SCC., Methods: All vulvar SCCs (201) were classified to be dVIN- (n=164) or uVIN related (n=37). Data with regard to the smear history and cervical histology were retrieved from PALGA, the nationwide Netherlands database of histo- and cytopathology. For HSIL cervical smears of which histology was taken, HPV DNA analysis on both the vulvar and cervical specimens was performed., Results: At least one smear was available in 145 (72%) of the 201 patients. Patients with a uVIN-related vulvar SCC more often had an HSIL compared with patients with a dVIN-related SCC (35 vs 2%, P<0.001). A total of 10 of the 13 HSILs were histologically assessed and identical HPV types were found in the vulva and cervix., Conclusion: These data emphasise the necessity to differentiate between dVIN- and uVIN-related vulvar tumours and to examine the entire lower female ano-genital tract once an uVIN-related lesion is found.

Purpose: High-risk human papilloma virus (HPV) plays a role in the development of a subset of vulvar squamous cell carcinomas. Uncertainty exists about the true impact of HPV in this tumor type because conflicting reports have been published with diverging prevalence rates. This study was done to fine tune the role of high-risk HPV infection in vulvar squamous cell carcinoma development in relation to clinical prognosis., Experimental Design: 130 vulvar squamous cell carcinomas of patients with known survival data were analyzed for histology of the adjacent lesion (differentiated or HPV-associated usual vulvar intraepithelial neoplasia), in relation to p16(INK4A) expression as marker of HPV activity, and presence and integration of high-risk HPV DNA., Results: Usual vulvar intraepithelial neoplasia was present adjacent to vulvar squamous cell carcinoma in 25 of 130 cases. Usual vulvar intraepithelial neoplasia-associated squamous cell carcinomas had high p16(INK4A) expression, and 24 of 25 squamous cell carcinomas contained integrated high-risk HPV DNA. Differentiated vulvar intraepithelial neoplasia was found adjacent to 105 of 130 vulvar squamous cell carcinomas. High-risk HPV was detected in 11 (10.5%) differentiated vulvar intraepithelial neoplasia-associated vulvar squamous cell carcinoma but correlated with high p16(INK4A) expression in only one case. Integration of viral DNA was never observed in differentiated vulvar intraepithelial neoplasia-associated squamous cell carcinomas, which suggests that a causal relationship of high-risk HPV in differentiated vulvar intraepithelial neoplasia-associated tumors is highly unlikely. The disease-specific survival of the differentiated vulvar intraepithelial neoplasia-associated vulvar squamous cell carcinoma patients was significantly worse compared with patients with a usual vulvar intraepithelial neoplasia-associated tumor., Conclusions: High-risk HPV is causally associated with the development of usual vulvar intraepithelial neoplasia associated squamous cell carcinomas, which comprise 19% of all vulvar squamous cell carcinomas, but not with differentiated vulvar intraepithelial neoplasia-associated vulvar squamous cell carcinomas. Differentiated vulvar intraepithelial neoplasia-associated vulvar squamous cell carcinomas have a significantly worse prognosis.

Objective: The purpose of the present study is to investigate the trends in incidence of both usual (u) and differentiated (d) vulvar intraepithelial neoplasia (VIN) separately, their malignant potential and the relation with other HPV related anogenital lesions in the Netherlands during a 14-year-period., Methods: The incidences of both types of VIN and vulvar SCC were retrieved from the Nationwide Netherlands Database of Histo- and Cytopathology. Population data were retrieved from the Database of Statistics Netherlands., Results: In the study period, the incidence of uVIN and dVIN increased, while the incidence of vulvar SCC remained stable. The overall percentage of uVIN patients that were later diagnosed with vulvar SCC was 5.7%, which was significantly lower than the percentage for dVIN patients (32.8%). In addition to this 5.6-fold increased conversion rate, the time of progression from dVIN to SCC development was significantly shorter than that of uVIN (p=0.005). Percentage of uVIN patients that were later diagnosed with SCC significantly increased with age (p=0.005), whereas the time to SCC significantly shortened with age (p=0.05). Forty-one percent of uVIN patients had a past, concomitant or future HPV-associated lesion of the lower genital tract, which is in contrast to the 3% for dVIN patients., Conclusions: An increase in diagnoses of both uVIN and dVIN has not led to an increase in vulvar SCC incidence. The malignant potential of dVIN is higher than that for uVIN. For uVIN the malignant potential increases with age.

Two pathways leading to vulvar squamous cell carcinoma (SCC) exist. The expression of proliferation- and cell-cycle-related biomarkers and the presence of high-risk (hr) HPV might be helpful to distinguish the premalignancies in both pathways. Seventy-five differentiated vulvar intra-epithelial neoplasia (VIN)-lesions with adjacent SCC and 45 usual VIN-lesions (32 solitary and 13 with adjacent SCC) were selected, and tested for hr-HPV DNA, using a broad-spectrum HPV detection/genotyping assay (SPF(10)-LiPA), and the immunohistochemical expression of MIB1, p16(INK4A) and p53. All differentiated VIN-lesions were hr-HPV- and p16-negative and in 96% MIB1-expression was confined to the parabasal layers. Eighty-four percent exhibited high p53 labeling indices, sometimes with parabasal extension. Eighty percent of all usual VIN-lesions were hr-HPV-positive, p16-positive, MIB1-positive and p53-negative. Five (of seven) HPV-negative usual VIN lesions, had an expression pattern like the other HPV-positive usual VIN lesions. In conclusion, both pathways leading to vulvar SCC have their own immunohistochemical profile, which can be used to distinguish the 2 types of VIN, but cannot explain differences in malignant potential., ((c) 2008 Wiley-Liss, Inc.)

Lichen sclerosus, high-grade usual vulvar intraepithelial neoplasia (VIN) and differentiated VIN have a different malignant potential. The objective of this study was to quantify the proliferative activity in the basal region of the epithelium of vulvar premalignancies. Furthermore, we investigated whether MIB1 expression in the basal region of vulvar epithelium can be helpful in diagnosing differentiated VIN, which may be hard to discern from normal epithelium. MIB1 was used to immunohistochemically visualise proliferating cells within formalin-fixed, paraffin-embedded, archival tissue sections of different vulvar premalignancies (N=48) and normal vulvar epithelium (N=16). Automatic digital image analysis software was developed to quantify the proliferating fraction in different parts of the epithelium (MIB1 positivity index). MIB1 expression differed among the various vulvar premalignancies; a MIB1-negative basal cell layer was a distinct feature of normal vulvar epithelium. No MIB1-negative basal cell layer was noted in differentiated VIN or other vulvar premalignancies. Owing to this negative cell layer, the MIB1 proliferation index in normal vulvar epithelium was significantly lower than in vulvar premalignancies. In conclusion, MIB1 expression can be a helpful tool in diagnosing a premalignancy and has additional value especially to distinguish differentiated VIN neoplasia from normal vulvar epithelium, but cannot explain the differences in malignant potential.

Two separate pathways leading to vulvar carcinoma have been suggested. First, a human papillomavirus (HPV)-dependent pathway, in which premalignant stages of vulvar cancer are the classic vulvar intraepithelial neoplasia (VIN) lesions. Second, an HPV-independent pathway, associated with differentiated VIN III lesions and/or lichen sclerosus. To obtain insight into the mechanisms underlying these pathways, we determined the relationship between HPV DNA and the expression of p14(ARF) and p16(INK4A) in non- and (pre)malignant vulvar lesions. Seventy-three archival samples of non- and (pre)neoplastic vulvar lesions were selected and tested for hr-HPV DNA using a broad-spectrum HPV detection/genotyping assay (SPF(10)-LiPA) and the expression of p14(ARF) and p16(INK4A). The prevalence of HPV increased with the severity of the classic VIN lesions; in VIN I no hr-HPV was detected, in VIN II 43%, and in VIN III 71% of the samples were hr-HPV-positive. Roughly the same was true for the expression of p14(ARF) and p16(INK4A). The simultaneous expression of p14(ARF) and p16(INK4A) was highly associated with the presence of hr-HPV DNA. Hr-HPV was detected in only a single case of the differentiated VIN III lesions, whereas no expression of p14(ARF) was found and 16(INK4A) was present in only two cases. All 16 samples of vulvar cancer were hr-HPV DNA- negative, although in respectively 63% and 25%, p14(ARF) and p16(INK4A) was expressed. No relation was found between hr-HPV and the expression of p14(ARF) and p16(INK4A) in the 20 nonneoplastic vulvar lesions. Our results provide further evidence that vulvar squamous cell carcinoma is a multifactorial disease that develops from two different pathways. First, an HPV-dependent pathway with a remarkable resemblance to CIN lesions and cervical carcinoma and second, an HPV-independent pathway in which differentiated VIN III lesions that are hr-HPV-negative may be precursors.